1. Field of the Invention
The present invention relates an endoscope and, more particularly, to an endoscope having an instrument raising device for adjusting the direction of an instrument such as forceps inserted in a living body cavity by using the endoscope.
2. Description of the Related Art
As is known, a medical endoscope such as a gastroscope or a duodenal scope is used to perform observation, treatment, and the like of a morbid portion upon insertion of the insertion portion of the endoscope into a cavity of a patient. When sampling of tissue for biopsy or medical treatment is to be performed by using forceps while a morbid portion is observed, a forceps raising device is used to direct the forceps toward the morbid portion. The forceps raising device is basically constituted by a forceps raising base rotatably mounted at the distal end portion of the insertion portion, and an operation wire coupled to the forceps raising base. The angle of the forceps raising base is adjusted by reciprocating the operation wire using a manual operating portion. The direction of the forceps is set by this adjustment.
While the endoscope is in use, fluids in a body cavity enter a forceps raising base housing chamber, in which the forceps raising base is housed, and the guide tube of the operation wire. Therefore, the device must be cleaned after it is used. A cumbersome operation is required for the cleaning of the device, especially the guide tube of the operation wire, because the tube is thin, and the operation wire is inserted therein.
In order to solve such a problem, a device having an entrance preventing member (packing) formed at the opening portion of the distal end of a guide tube is disclosed in Jpn. UM Appln. KOKAI Publication Nos. 52-67790 and 52-38986.
Another device is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 56-8030, in which a forceps raising base, an operation wire, and a tubular inner layer member (a guide tube is constituted by a tubular outer layer member (tube member) and the tubular inner layer member (closed coil member)) are designed to be detachable so as to facilitate a cleaning operation.
Still another device is disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 4-314439 and 57-75629, in which a distal end cover is designed as a detachable member to facilitate the cleaning of a forceps raising base housing chamber.
According to Jpn. UM Appln. KOKAI Publication Nos. 52-67790 and 52-38986, however, entrance of intracavity fluids cannot be prevented completely in practice.
According to Jpn. Pat. Appln. KOKAI Publication No. 56-8030, since the forceps raising base housing chamber serves as a blind alley, a cumbersome operation is required to clean the chamber, and intra-cavity fluids leaking from the closed coil member enter the tubular outer layer member. For this reason, it cannot be said that the cleaning of this device is extremely facilitated as compared with the device disclosed in Jpn. UM Appln. KOKAI Publication Nos. 52-67790 and 52-38986. That is, in the device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 56-8030, since the opening portions of the two ends of the guide tube are narrow, and the inner diameter of the tube is larger than the diameter of each opening portion, a cleaning operation is difficult to perform. In addition, a stopper member must be removed.
A cumbersome operation is also required for the cleaning of the device disclosed in Jpn. Pat. Appln. KOKAI Publication Nos. 4-314439 and 57-75629.